Spark arrester cap for incinerators



June 12, 1934. w. H. CARRINGTON SPARK ARRESTER CAP FOR INCINERATORS I Filed June 7, 1932 Patented June 12, 1934 UNITED STATES PATENT? OFFICE 5 Claims.

The stacks of incinerators of garbage, refuse and other waste or semi-waste material are usually provided with some sort of pervious cover to prevent the escape of sparks, burning embers and bits of flaming material.

One object which I have in view is the provision of an improved pervious cap for incinerator stacks which will more efficiently prevent the escape of sparks, burning embers and flaming particles, and which will be more permanent and durable than the types of such devices now in use.

Again the pervious covers now in use tend to become clogged or partially clogged by paper and other similar sheet material which is driven upward by the stack draught and is lodged against the underside of the cover.

Therefore, another of the objects which I have in view is the provision of means for preventing such clogging and of insuring the consumption of all such material.

Moreover incinerator stacks are usually built in standard sizes dependent upon the capacity of the incinerator, such for instance of twelve inch, eighteen inch, twenty-four inch, etc., inside measurement.

Therefore another object which I have in view is the provision of means whereby one of my improved caps may be adapted at relatively slight expense to various sizes of stacks without requiring alteration in the structure of the cap, thus avoiding the additional expense which would otherwise be incident to the manufacture and stocking of commercial quantities of numerous sizes of caps.

Other objects will appear from the following description.

In the accompanying drawing, wherein I have illustrated a practical embodiment of the principles of my invention, Fig. 1 is a plan View of the incinerator stack cap.

Fig. 2 is a reduced side elevation of the same removed from the stack, the cap being partially broken away in section to better show its construction.

Fig. 3 is a bottom plan view of the paper-arrester which is shown in side elevation in Fig. 2.

Fig. 4 is a plan view of the wire-mesh stretcher bars which hold the wire-mesh lining in place in the cap.

Fig. 5 is a diagrammatic view showing how a rectangular sheet of wire-mesh lining is prepared for insertion in the cap.

Fig. 6 is a broken side elevation, on reduced scale of the adapter which I use to adapt the cap to larger sizes of stacks.

Fig. '7 is a broken plan view of the adapter.

Fig. 8 is a fragmentary vertical section of the adapter on enlarged scale.

Referring first to Figs. 1 to 5, inclusive, of the drawing, the cap comprises a grid frame, usually and preferably cast, a wire mesh lining for the grid frame, and stretchers to hold the latter in p ace.

The base of the grid frame is usually of rectangular form and has an angular cross-sectional shape, as shown in Fig. 2. Its vertical flange 1 fits downwardly within the throat of the stack while the horizontal flange 2 rests upon the top of the stack. The stack is indicated in dotted lines at 3 in Fig. 2.

Rising from the corners of the base are the corner ribs 4 which are arcuate and meet at the center 5. 6 represent the intermediate ribs also arcuate and rising from the sides of the base to the common center 5. Connecting themain ribs 4 with the base at uniform intervals are the secondary ribs 7, thus forming a grid.

While the cap may be assembled of separate elements I prefer to form the base and the main and secondary ribs by casting them as an integral whole.

If desired the ribs may be straight instead of arcuate, but I prefer to employ the curvilinear dome contour as shown.

In the case of a circular stack the base may be annular to fit the throat of the stack instead of rectangular, but incinerator stacks are usually built with throats of rectangular cross sectional shape.

Held against the underside of the grid formed by the upwardly converging ribs is a lining 8 of wire mesh usually formed of copper, bronze or other material which will not rust or corrode. The mesh is fine enough so that sparks, burning embers and flaming particles will be arrested.

The lining 8 is of dome-shape to fit against the under side of the grid.

In Fig. 5 I illustrate how the lining may be formed of a rectangular sheet of mesh indicated in dotted lines at 8a. The cuts 8b are made from the corners of the sheet extending toward but not to the center of the sheet and the cut sheet is then placed in the interior of the cap and pressed into position, the edges of the cuts 8b overlapping to permit the sheet to assume the required dome-shape.

The wire mesh lining 8 is held in position by any convenient means. Thus I may use the stretcher bars 9 which may be formed by stamping out a sheet of non-rusting and non-corrodible metal, such as brass, to produce the spider arrangement illustrated in Fig. 4, the bars 9 uniting at their inner ends with the center 10.

If desired separate bars of sufficient length to span the inside of the grid may be employed, the bars crossing each other at the center.

The material of the bars should be resilient enough, so that when they are bowed to fit against the inside of the lining 8, they will bear against the lining and hold it snugly in position.

The top center of the grid is pierced by a vertical hole, and the center 10 of the stretcher bar is similarly pierced.

The reduced upper end of is screwed down on the threaded upper end of the rod, thus clamping the grid, the lining and the stretcher bars together.

The lower ends of the stretcher bars 9 may be attached tothe depending flange 1 of the base by means of the cap screws 13 extending through holes in the bent ends of the bars and engaging threaded holes in the base, as illustrated in Fig. 2.

The rod extends downwardly in the throat of the stack and is provided at its lower end with a spider -14-having acenter with radially disposed fingers 15 having downwardly inclined ends 16.

Any paper or similarly extended material flying up the stack will be caught by the fingers 15 and held in the path of the flames against further ascent until consumed. Thus'there is no chance for the paper or other material to flatten against the underside of the cap and thus choke or partially choke the draught.

The spider 14 should be located at a suitable distance below the cap, say two or three feet.

'In practice I prefer to manufacture my im proved caps to fit the smallest standard stack size, twelve, inches in inside measurement, and to employ adapters to accommodate the caps to stacks of larger sizes.

However where the demand is sufficient the standard caps may be made in several of the more generally used sizes and adapters used to fit the caps to other stack sizes.

The adapter also comprises a grid, a wire mesh lining and stretcher bars.

/ The adapter grid is formed of a lower frame 17 and an upper frame 18 supported from the lower frame by the upwardly and inwardly inclined corner ribs 19, while between the corner ribs the ribs 20 also connect the frames with the short ribs 21 connecting the lower frame to the corner ribs adjacent to the corners.

The frames and ribs are preferably formed of an integral casting.

The lower frame is provided with 2. depending flange which fits down into the throat of the stack while the outwardly extending horizontal flange rests on top of the stack, the stack being indicated in dotted lines at 22 in Fig. 6.

The upper frame 18 comprises an open boxing into which fits the depending flange 1 of the cap, the horizontal flange 2 of the cap resting upon the top edges of the upper frame. The cap is indicated in dotted lines in Fig. 6.

The sides of the adapter are lined with panels 23 of wire mesh cut in proper shape to fit with their top edges extending up within the top frame 18 and upset horizontally over the frame as shown at 24.

The panels are held in place against the inside of the grid by means of flat stretcher bars 25 whose ends are bent over and held in position by bolts 26 extending through the ends of adjacent.

a depending rod. 11 extends up through said holes and a nut 12 The caps may be made in one or more of the most commonly used sizes, and may be installed by means of adapters to any other size of stack.

1. An integrally cast metal cap for an incinerator stack which comprises a base frame having a flat under surface adapted to rest upon and be supported by the top of the incinerator chimney, a skirt flange on said base arranged to depend within the chimney flue and adjacent the walls thereof" to prevent horizontal displacement of the cap relative to the chimney, upwardly converging ribs rising at spaced intervals from said frame and an elevated center into which said ribs merge at their upper end, and a wire screen within said cap and held in place against the inner surfaces of said ribs.

2. An integrally cast metal cap for an incinerator stack which comprises a base frame having a flat under surface adapted to rest upon and be supported by the top of the incinerator chimney, a skirt flange on said base arranged to depend within the chimney flue and adjacent the walls thereof to prevent horizontal displacement of the cap relative to the chimney, upwardly converging ribs rising at spaced intervals from said frame and an elevated center into which said ribs merge at their upper end, a wire screen lining within said cap, and bowed metal spacer bars bearing against the inner surface of said screen to hold the latter extended in place.

3. An integrally cast metal cap for an incinerator chimney which comprises a rectangular frame having a flat under surface adapted to rest upon and be supported by the top of the chimney,

four ribs rising from the corners of said base and converging upwardly, a center into which the upper ends of the ribs merge, and lesser ribs extending upwardly in spaced relation from said base and with their upper ends merging with the first named ribs, to form a grid, and a wire lining for said cap to form a spark arrester.

4. An integrally cast metal cap for an incinerator chimney which comprises a rectangular frame having a flat under surface adapted to i rest upon and be supported by the top of the chimney, a skirt flange depending from the base within the chimney flue adjacent the walls of the latter to anchor the cap in place, fourribs rising from the corners of said base and converging upwardly, a center into which the upper ends of the ribs merge, and lesser ribs extending upwardly mensions than the base frame supported by said ribs, a pervious cap having a flat bottom frame adapted to rest upon and be supported by the top frame of the adapter, and a skirt flange depending from the bottom frame of the cap within the top frame of the adapter and adjacent the 'ini'i'er wall surfaces of the latter to,;.prevent horizontal displacement of the cap relative to the adapter.

WALTER H. CARRINGTON. 

